The present invention relates to a fired cartridge and bullet examination imaging apparatus for use during forensic analysis of spent firearm cartridges. The invention relates further to a method of capturing encoded geometric shapes or alpha numeric character images which are embossed or tool marked onto the cartridge surfaces by the specific firearm that expended the cartridge.
Mechanical forensics and ballistics investigations are undertaken in most crime investigations, accident reconstruction or other situations in which one or more weapons was discharged during the commission of the crime, by accident or perhaps for justifiable cause. Reconstruction, investigation and prosecution, of all incidents of firearm use can be made easier when it is possible to show that a particular weapon was used or discharged during the specific incident being investigated or reconstructed.
It is well known, however, that bullets and cartridge cases that have been fired from a firearm will bear markings from contact between the bullets or cartridge cases and the surfaces of the firearm with which the bullets and cartridges come into contact. For example, the rifling of the barrel will emboss rifling and other marks on a bullet, and the firing pin, extractor, interior of the breach and face of the bolt will leave markings on the cartridge case. Certain such markings are general to a given type of firearm, and may this aid in identifying a type of firearm, while others are unique to each firearm and may thereby be used to identify a given firearm.
The markings most useful for identifying a given, specific firearm, however, are pseudo repeatable and random and take the form of xe2x80x9cscratches and dingsxe2x80x9d termed xe2x80x9cBallistic Finger Printsxe2x80x9d which are non-specific in nature. Firearms experts, however, by microscopic examination of fired bullets and cartridges (casings or shells), firearms have traditionally been able to compare markings to identify whether fired bullets or spent cartridges originate from a given firearm. There exist, for example, databases of xe2x80x9cBallistic Finger Printsxe2x80x9d or xe2x80x9cScratch and Dingxe2x80x9d Images of bullets and cartridges recovered from crime scenes, for example, which may be subsequently used to match a firearm to a given crime scene by matching samples of fired cartridges and bullets with the archived xe2x80x9cBallistic Finger Printsxe2x80x9d or xe2x80x9cScratch and Dingxe2x80x9d images.
Unfortunately, investigators often have limited evidence to work with in order to determine the facts related to the situation at hand, for example, when the used firearm is unavailable, missing, unrecoverable or numerous weapons were discharged. For example, it is very common for the perpetrator of a shooting to take the firearm away with him after committing a crime, and often the only evidence left behind is the discharged bullets themselves, if they can be found, and the spent shell casings. While scratches, marks and/or other indicia on a spent bullet or shell casing can assist an investigator with connecting the spent shell casing or bullet with a given firearm, the identification usually requires possession of the firearm itself, for comparison purposes, is often difficult even when the firearm is available.
Currently, such forensic investigations are expensive and time consuming and require personal training and sophisticated equipment that not every law enforcement department has or can afford.
A concept referred to as xe2x80x9cBallistic Taggingxe2x80x9d, however, may be used to mark cartridges or bullets or both with specially encoded geometric shapes, holograms, alphanumeric codes, barcodes and other specific coding techniques which are not random and are which are completely repeatable and which are unique to each firearm. Such methods would in addition be more reliable and less expensive and time consuming by not requiring the costly apparatus, imperfect imaging algorithms, non-uniform lighting, non-standardized procedures and cross jurisdictional data bases used to store xe2x80x9cBallistic Finger Printsxe2x80x9d or xe2x80x9cScratch and Dingxe2x80x9d Images.
There are currently available a variety of systems for forming or micro-engraving images, shapes or symbols in or on an exterior surface of an object, such as a firing pin or the interior of the chamber or barrel of a firearm, such that, an image, shape of symbol is embossed or otherwise marked on a surface of a cartridge by the normal operation of the firearm, such as firing of a cartridge or the loading or ejection of a cartridge. Such images, shapes or symbols, hereafter referred to generally as xe2x80x9cimages, may take any graphic form, including abstract symbols or brands, letters or numbers, and so on, and are typically formed of raised areas of a surface or of surface indentations, such as holes, vias, blind vias or some other form of surface indentation, or any combination thereof.
As a result, fired bullets or cartridge cases or both may be left with markings from the firearm from which they come. These markings result from forced contact with metal parts in the firearm bearing such images, such as an interior face of the chamber, bolt or barrel or an engraved xe2x80x9cmarkerxe2x80x9d embedded in or mounted on such a surface, and may be unique to given firearm by the engraving of an image unique to the firearm during manufacture or as a result of a subsequent refitting or retro-fitting.
The advantages of such marking of bullets and cartridges can be realized, however, only if there exist methods and apparatus for simply, inexpensively and reliably reading the markings, and for correlating the markings on a bullet or cartridge with a given firearm.
It is therefore an object of the present invention to simplify and therefore to improve the automated process of fired cartridge and bullet imaging and analysis, to eliminate the need for complex image algorithms, to reduce the chances of human error, and to eliminate at least some of the need for mapping xe2x80x9cScratches and Dingsxe2x80x9d of fired cartridges, termed a xe2x80x9cBallistic Finger Printxe2x80x9d.
The present invention is directed to a method and apparatus for identifying and tracing firearms by analysis of the cartridge shell casings and/or projectiles. This technique was developed to assist with both foreign and domestic law enforcement and government gun control programs.
According to the invention there is provided a fired cartridge imaging apparatus comprising a fired cartridge mounting device for holding the cartridge wherein the cartridge is substantially aligned normal to the axis of illumination, and viewing from the microscope based imaging apparatus a primer surface of the cartridge, the primer surface being substantially perpendicular to the axis of illumination. The apparatus includes a cartridge microscope having an optical axis and, mounted with the optical axis substantially parallel to the longitudinal axis, a focusing means for focusing the microscope to image a breech face encoded impression on the primer surface and a encoded firing pin impression surface in the primer surface. An optimized holographic imaging system is integrated into a mono-chromatic and multi-chromatic illuminator to provide illumination from various angles onto the working area of the microscope apparatus that is being viewed and to provide a non-shadowing intensity variable light.
The task of the imaging apparatus is to capture images of organized images, structures, codes and/or encoded alphanumeric codes or holograms which have a specific meaning that is irrefutable, such as a serial number of the firearm or some code that represents a positive identification of a specific firearm.
The method and apparatus of the present invention provide an apparatus which can switch between several magnifications suitable to view the geometric encoded hologram or alphanumeric codes and other indicia on the breech face, primer surface and other surfaces of a cartridge or bullet.